The secure_load function in gluon/utils.py in web2py before 2.14.2 uses pickle.loads to deserialize session information stored in cookies, which might allow remote attackers to execute arbitrary code by leveraging knowledge of encryption_key.
Conclusion & alert: CVE-2016-3957 is rated High Exploit Risk (81.1/100): CVSS Critical severity, with high exploitation likelihood (EPSS 4.99%, 91th percentile). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 12.74% | 4.99% | -7.75% |
| 2 | 2025-08-23 | 13.31% | 12.74% | -0.57% |
| 3 | 2025-07-23 | — | 13.31% | — |
Full EPSS history (18 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
ubuntu
|
medium | CVE-2016-3957 medium priority: Ubuntu including 1 source packages (web2py), 7 status rows across 7 suites (artful, bionic, cosmic, disco, trusty, upstream, xenial): DNE 4, ignored 1, needs-triage 1, released 1. | https://ubuntu.com/security/CVE-2016-3957 |
| URL | Tags |
|---|---|
| https://devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/ | Exploit Technical Description Third Party Advisory |
| https://github.com/web2py/web2py/blob/R-2.14.1/gluon/utils.py#L200 | Third Party Advisory |
| https://usn.ubuntu.com/4030-1/ |